(CNN) -- Immigrants showed up at courts across the United States on Thursday for hearings they'd been told were scheduled but that didn't exist.
Official paperwork they'd been given by immigration authorities wasn't accurate.
Immigration lawyers first told CNN last year that they'd been observing a wave of "fake dates" pop up, describing it as an illustration of how dysfunctional the system had become and how chaotic the Trump administration's approach to immigration enforcement can be.
Inside a packed waiting room at the Arlington Immigration Court on Thursday, confused immigrants clutching paperwork asked lawyers for help. Some said they'd driven hours to get to court and had awakened at 3:30 a.m. to arrive on time.
"I'm left with a question mark. I'm wondering, 'Why?' " said Bigail Alfaro, 39, who's seeking asylum with her two children. "I'm afraid and nervous."
As she prepared to head into court for a scheduled hearing, immigration attorney Eileen Blessinger found herself fielding questions and asking court officials to stamp paperwork to provide proof that immigrants had shown up.
"What happened?" one woman asked her.
"You don't have court, because they made a mistake," Blessinger said.
At an immigration court in Atlanta, a crowd of around 40 people were turned away, almost one by one, by a Spanish-speaking court employee telling people with notices that their hearings had been "postponed."
Among those showing up for court were parents with small children, some dressed only with hooded sweatshirts and covering themselves with blankets, with the temperature in Atlanta in the mid-20s.
"They told us they would send us another citation by mail," said a man named Jose who asked to be identified only by his first name. "But who knows when? And the hard part is they don't let us know with enough time, enough time to prepare ourselves."
It isn't yet clear how many people were affected nationwide on Thursday. The American Immigration Lawyers Association says it's tracking the issue.
The Executive Office for Immigration Review, the division of the Justice Department that runs the nation's immigration courts, said in a statement that the office "was unable to proceed with hearings for some respondents who believed they had hearings scheduled." The office indicated a combination of factors had resulted in the confusion, including some weather-related court closures and the recently ended partial government shutdown.
"In some cases, the cases had been rescheduled to another date, but the lapse in appropriations prevented the immigration courts from issuing new hearing notices far enough in advance of the prior hearing date. In other cases, EOIR did not receive the Notice to Appear in a timely manner," the statement said.
Immigration attorneys say "fake dates" unfairly burden immigrants and create more pressure on a system that's already suffering from a crushing backlog.
"Imagine the stress of facing potential deportation," North Carolina immigration attorney Jeremy McKinney said on Twitter. "You're told show up in court or be ordered deported in your absence. You drive hundreds of miles & wait in line only to be told the court date was not real. 'Sorry for the minor logistical errors.' "
The US Supreme Court ruled in June that notices to appear -- the charging documents that immigration authorities issue to send someone to immigration court who's accused of being in the United States illegally -- must specify the time and place of proceedings in order to be valid.
Since then, immigration lawyers across the country have reported that officials are increasingly issuing such notices with so-called "fake dates," ordering immigrants to appear at hearings that, it later turns out, were never scheduled in immigration courts.
For instance, lawyers reported examples of notices to appear issued for nonexistent dates, such as September 31, and for times of day when courts aren't open, such as midnight.
In its statement Thursday, the Executive Office for Immigration Review said it had issued policy guidance in December and modified its system so the Department of Homeland Security and its components can directly schedule hearings.
The agency said it "does not expect any further recurrence of this type of situation."